Author Topic: Solar dishwasher is up and running  (Read 820 times)

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OperaHouse

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Solar dishwasher is up and running
« on: September 26, 2017, 01:40:58 PM »
My wife had been complaining about washing dishes at the camp.  Came home a couple weeks ago from town recycling with a 2 year old GE dishwasher.  Guy was about to toss it in the dumpster when I asked to have it said it was hit by lightning. It had indeed taken a major strike, but the protection devices had done their job and damage was limited to power section.

Turns out the major load of a dishwasher is the heating element.  Pumps and everything else is limited to 100W peak and generally runs at about 65W.  I have 120F water and the control system will fault if water temps don't reach 120F during wash cycle.  120V heating element is 17 ohms. At 60V panel DC buss that will give about 1/4 the heating and these don't really use that much water each cycle.  A fill doesn't consume enough water to get hot water to the washer.

My initial solution was to add extra insulation to the housing, externally power the heater from the 60V PV buss switched on and off by the dishwasher control, and run the discharge pump for 20 seconds anytime the fill valve is operated.  I had noticed when testing the washer in the garage that the discharge pump would turn on and off every couple seconds for a few times.  Figured that was some feature to prevent screen clogging.  When dishwasher was finally installed, for the first 20 seconds of fill the water would just dribble out.  Turns out this on/off cycle was to get rid of air trapped in the pump.  Moving on I just removed the interval on timer and decided to see how it would work without it. 

So far with three washings water temp hasn't been an issue. Normal cycle takes about 80WH in a 50 minute period.  I only ask her to run hot water at the sink for a minute to warm up the pipes and do dishes mid day.  And heated dry doesn't really cost me anything. No need for a big inverter.  I use a 700W MSW with the fans removed to save power.  The control system fits nicely in this old alarm cabinet.

kitestrings

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Re: Solar dishwasher is up and running
« Reply #1 on: September 29, 2017, 08:15:19 AM »
Sounds like a good solution, and nice re-use of an appliance headed for the curb.

We have a "dish drawer" I think it's called.  F& P makes a split dishwasher that has a separate upper and lower drawer, with the idea being that you run just the upper section for the normal, light duty, day to day, and the lower section for pots and pans.  We have just the upper section and just try to be more creative about loading it.  Similarly, I try to run the hot water tap for a couple minutes to get the water from our on-demand (LPG) water heater to the kitchen before kicking it off.

Most days, particularly in the summer we use the built in timer - many newer models you can press to turn on, or press and hold to scroll to a 1, 2, 3 ,4-hr delay - to set it to begin mid-afternoon so it coincides with our solar production for the day.

OperaHouse

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Re: Solar dishwasher is up and running
« Reply #2 on: September 29, 2017, 09:16:56 AM »
The more things change, the more they stay they stay the same.  I was cooking breakfast and was looking for  particular pot. Asked my wife if the dishes in the washer were clean, "No, I'm waiting for the sun."  The delay timers are nice.

I have some washing machine fill valves.  Instead of running the pump, I think I'll just have this valve open to dump some water before the fill valve is operated.  So far it has not thrown any temp faults so that is in the that would be nice list to do.  Next year I will mod up a large LG washer to work on solar and avoid generator noise.

kitestrings

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Re: Solar dishwasher is up and running
« Reply #3 on: September 29, 2017, 12:19:43 PM »
Regarding "are they clean?"...

We put together a magnetic photo frame where in one half there's a picture of one of the kids contemplating a puddle, if you flip it you see the same kid after his decision...


Bruce S

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Re: Solar dishwasher is up and running
« Reply #4 on: September 29, 2017, 01:34:14 PM »
OperaHouse;
If you run the fill valve , won't the water level sensor in the tub part of the dishwasher kick in and pump that water out?
OR is this what you intend to do so it cycles the temperate water?
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OperaHouse

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Re: Solar dishwasher is up and running
« Reply #5 on: September 30, 2017, 09:29:21 AM »
That was the idea. the dishwasher program gives ample time to fill the tub to cover varying water pressure conditions.  The high level switch just interrupts the fill valve directly.  It is a little strange that if there was no water that the dishwasher wouldn't know it. From tests it appears I have a good 20 seconds I can waste.  I could pulse the pump but that seems like it might take extra time.  It is easier just to have a valve open for 15 seconds to flush water through the house pipes and then allow it to fill the washer.  We are coming on cold times and that extra step may be needed as the water heaters are outside the house in the power shed.  Those will be some cold pipes that have to warm up.

Bruce S

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Re: Solar dishwasher is up and running
« Reply #6 on: October 02, 2017, 07:57:42 AM »
That idea helped me with our outside sink!. I have those fill valves just waiting for a reason to be used. I quickly wired one up to a foot switch, once pressed it allows the water to start being pumped from the 15gal grey water and rain water barrel. We use this for de-mucking . I've learned that coffee and potting soil are not compatible when trying to quench my thirst.
So I set up a cute little SS sink , but didn't want to leave the tubes connected to outside faucet (we're coming up on fall/winter and it get completely turned off inside the house and the valve allowed to dry before closing.

Using you're idea, I hooked up a waterproof setup that runs a small submersible pump that merely recirculates the water. The soap keeps the bugs at bay and my coffee tastes much better. 
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DamonHD

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Re: Solar dishwasher is up and running
« Reply #7 on: October 02, 2017, 09:49:17 AM »
I've learned that coffee and potting soil are not compatible when trying to quench my thirst.

Maybe you've been spending too much on coffee and too little on soil.  The right price could make them interchangeable...

(Now I have started using a little French press for my nice coffee, I must make more of an effort to get the spent grounds to the compost heap where they should become soil...)

Rgds

Damon
« Last Edit: October 03, 2017, 12:31:34 AM by DamonHD »

Bruce S

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Re: Solar dishwasher is up and running
« Reply #8 on: October 02, 2017, 10:11:10 AM »
While those French presses are "nice" they're too labor intensive for me.
One of the more interesting things I've found by talking with field people who do extensive studies; is that it not the ground that worms like it's the caffeine. Worms actually don't like the grounds (it hurts their skin), but like humans they get a rush from the caffeine.

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DamonHD

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Re: Solar dishwasher is up and running
« Reply #9 on: October 02, 2017, 10:44:05 AM »
Well, well, you learn something every day.

Still, I'm happy with hyper worms chewing the rest of the stuff double-quick.

Rgds

Damon

Bruce S

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Re: Solar dishwasher is up and running
« Reply #10 on: October 02, 2017, 12:16:00 PM »
OperaHouse;
The demand relays you have , are they 220Vac? The one's I'm using are out of a junked top loader that are USA voltage 120Vac. Worked out easy for me and I like the safety of the AC versus DC route.

Even new, the relays are pretty cheap cost wise.

Cheers
Bruce S
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george65

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Re: Solar dishwasher is up and running
« Reply #11 on: October 02, 2017, 11:50:36 PM »
Stupid me. Put post on wrong thread.  :0(




« Last Edit: October 03, 2017, 05:59:30 AM by george65 »

frackers

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Re: Solar dishwasher is up and running
« Reply #12 on: October 03, 2017, 03:40:28 AM »
Any chance that the shunt in one of them devices can be hacked to increase the current range?
Robin Down Under (Or Are You Up Over)

george65

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Re: Solar dishwasher is up and running
« Reply #13 on: October 03, 2017, 06:05:19 AM »

If you mean the meters in the misplaced post, yes. They come in 50 and 100A versions and the only thing different is the shut.
I re posted in correct thread.

OperaHouse

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Re: Solar dishwasher is up and running
« Reply #14 on: October 04, 2017, 08:54:47 AM »
Yes, this thread is about worms.

I was out on Cape Cod and at a McDonald's there was a corporate plackard on the counter that said they saves coffee grounds for gardeners. I've heard Starbucks has done that for years. When I went home I went to a McDonald's and asked if they saved coffee grounds and they looked at me like I was nuts.  My wife uses a French press and we dry out the grounds. Read an article about a Canadian company that mixed them with wax to make fire logs.  It said they had a higher heat content than sawdust.  Used to make these hamburger shaped fire starters with wax.

I use a double set of contacts in series to switch the heater in and out. I have boxes of these as manufacturers samples. I will switch to a FET next year. It makes little difference if the contacts burn out or weld shut as there is no safety concerrn.

Bruce S

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Re: Solar dishwasher is up and running
« Reply #15 on: October 04, 2017, 11:29:32 AM »
Yes, this thread is about worms.


Sorry about that, old habits dye hard.
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